Effects of vanadate on water and electrolyte transport in rat jejunum

The effect of vanadate (orthovanadate, VO 4 − ) on water and ion transport was studied in rat jejunum. Water transport was tested by single-pass perfusion in vivo and ion fluxes by the Ussing-chamber technique in vitro. The results suggest that vanadate has two actions on ion and water transport: (1) At low concentrations (10 −4 M) it causes Cl − , Na + and water secretion by stimulation of adenylate cyclase; (2) At higher concentrations (10 −3 and 10 −2 M) it decreases net absorption of Na + and Cl − by inhibition of (Na + + K + )-ATPase.